5 litres of water 250 grams rye sourdough bread - toasted almost burned 50 grams sultanas 40 grams sugar 2 tablespoons sourdough starter Bring the water to boiling point. Add the sultanas and toast to the very hot water. Soak overnight, 8 to 12 hours. Remove the bread and sultanas. Add the sugar and sourdough starter to the flavoured water. Allow the mix to ferment in a demijohn, lidded with a fermentation lock. IMPORTANT: Wait for the fermentation to stop - no more bubbles. Once bubbling stops, bottle the brew in crown top bottles. Add half a teaspoon of priming sugar to each bottle before crown topping. Don't bottle too early or the glass will likely explode! Keep the bottles warm for a day or two, then refrigerate. The kvass should be nicely carbonated by then. Serve cold. This might contain 0.5% to 1% alcohol.